Silicon nanocrystals (ncs) belong to an interesting class of semiconductor nanostructures that manifest size dependent electronic properties. This well known effect of quantum confinement can explain many properties of silicon ncs. However, with decreasing size and dimension of the ncs, the role of surface phenomena becomes substantial. For example, we have shown recently that the strong luminescence from these ncs should be assigned to the exclusion of nonradiative channels rather than to the enhancement of radiative inter-band transitions. In addition, using infrared intra-band transitions spectroscopy, we were able to resolve the quantized electronic sublevels of small silicon ncs. We have found that under appropriate conditions, these electronic sublevels are resonantly coupled to surface vibrations. We suggest that this coupling mechanism is responsible for the exclusion of nonradiative channels in silicon ncs.
|Number of pages
|Physica E: Low-Dimensional Systems and Nanostructures
|Published - Apr 2007
Bibliographical noteFunding Information:
This work was supported by a Grant #422/04 of the Israel Science Foundation (ISF) and by the Intel corporation grant. We thank Dr. Inna Popov from the Hebrew University Center for Nanoscience and Nanotechnology for the TEM analysis.
- Intra-band optical transitions
- Porous silicon
- Silicon nanocrystals